The Barthel Index should be used as a record of what the patient does do, not what they could do.
The main aim is to establish degree of independence from any help, physical or verbal, however minor and for whatever reason.
Use of aids to be independent is allowed.
The need for supervision renders the patient not independent.
A patient's performance should be established using the best available evidence. Asking the patient, friends/relatives and nurses are the usual sources, but direct observation and common sense are also important. Direct testing is not usually needed.
Usually the patient's performance over the preceding 24-48 hours is important, but occasionally longer periods will be relevant.
Middle categories imply that the patient supplies over 50 per cent of the effort.
References
Mahoney FA, Barthel DW. Functional evaluation: The Barthel index. Md State Med J. 1965; 14: 61-65.